National ITS Architecture Glossary

A document of the National Architecture that presents a scheme for implementing ITS services in a phased approach. This is part of an overall strategy that includes recommendations for future research and development, operational tests, standards activities, and training. The Implementation Strategy analysis and guidance is all based on service packages. It identifies the service packages that provide certain ITS services and recommends a phased deployment of those service packages to provide the most needed and most feasible user services initially, and less needed/feasible user services at a later date. The Implementation Strategy considers several items and issues regarding deployment, such as legacy systems, politics, funding, service package synergy, technology requirements, and standards requirements. Much of the service package-related analysis that is contained in the Implementation Strategy has been updated and included in the new Service Packages Document. The Service Packages Document is the authoritative source for all current information on the National ITS Architecture service packages.

Information that is exchanged between subsystems and terminators in the physical architecture of the National ITS Architecture. The terms "information flow" and "architecture flow" are used interchangeably. Information flows are the primary tool that is used to define the ITS architecture interfaces. These information flows and their communication requirements define the interfaces which form the basis for much of the ongoing standards work in the national ITS program.

An integral component of the National ITS Architecture that represents the existing and emerging institutional constraints and arrangements that are the context for all ITS deployments. The transportation layer and communications layer together provide the technical framework within which interoperable systems may be implemented. The institutional layer introduces the policies, funding incentives, working arrangements, and jurisdictional structure that support the technical layers of the architecture. This institutional layer provides the basis for understanding who the stakeholders will be and the roles these implementers could take in implementing architecture-based ITS systems.

The system defined as the electronics, communications or information processing in transportation infrastructure and in vehicles used singly or integrated to improve transportation safety and mobility and enhance productivity. Intelligent transportation systems (ITS) encompass a broad range of wireless and wire line communications-based information and electronics technologies.

See architecture interconnect.

The ability to connect, and connections between, differing modes of transportation.

Legislative initiative by the U.S. Congress that restructured and authorized federal funding for transportation programs; provided for an increased role for regional planning commissions/ MPOs in funding decisions; and required comprehensive regional and statewide longterm transportation plans. Superseded by the Transportation Equity Act for the 21st Century (TEA-21) in 1998.

See system inventory.

See element.

Defines an architecture of interrelated systems that work together to deliver transportation services. An ITS architecture defines how systems functionally operate and the interconnection of information exchanges that must take place between these systems to accomplish transportation services.

Access point for four Web-based resources that provide ready access to information supporting informed decision making regarding deployment and operations of ITS to improve transportation system performance. The four knowledge resources are the ITS Benefits Database, ITS Costs Database, ITS Deployment Statistics Database, and the ITS Lessons Learned Knowledge Resource. A fifth Web site, the ITS Applications Overview, provides access to information from each of the knowledge resources using an organization structure. The ITS Knowledge Resource Portal is available at www.ITSKnowledgeResources.its.dot.gov.

Any project that in whole or in part funds the acquisition of technologies or systems of technologies that provide or significantly contribute to the provision of one or more ITS user services.

Areas of ITS which can be used to enhance surface transportation security. The National ITS Architecture provides entities (subsystems and terminators), functions, and interfaces that cover aspects of the eight ITS security areas.